Shock absorber



E. S. CHURCH ET AL SHOCK ABSORBER Filed March 20,

E. S. CHURCH ET AL SHOCK ABSORBER Filed March 20, 1922 2 Sheets-Shee1 2 M my Patented duly ll,

ELLIUTT S. CHURUPI, @ll MEWTQN, AND FREDERIQK J. SHEFME, dhh, F AUBURN- DALZE, MASSAGIHLUSETTS.

ABSURBEE.

application filed March as, 1922. fierial lilo. Miami.

To all whom it may concern:

Be it known that we, Ennrorr S. (lemon and FREDERICK J. SHEPARDJJL, both citizens of the United States, residing, respectively, at Newton, in the county of Middlesex and State of Massachusetts, and Anburndale, in

the county of Middlesex and State of Massa chusetts, have invented new and useful Tmprovernents in Shock Absorbers, of which the-following is a specification.

This invention relates to shock absorbers particularly intended to check excessive recoil of vehicle springs when the vehicle is in motion and is of that type'which makes use of fluid pressure, the flow of which in one direction is more or less restricted, while in the other direction is comparatively tree.

The present invention provides a construction by which the extent of restriction of the flow is increased with increased speed of recoil so that the retarding efi'ect is increased, but which acts to decrease the restriction as the speed of recoil decreases so that the recoil is arrested easily and without shock re gardless of the'degree of roughness of the road being traveled or the extent of flexing movement of the springs, the recoil of which is to be checked.

For a more complete understanding of this invention, together with further objects and advantageous details and combinations of parts reference may be had to the accompanying drawings in which Figure 1 is a side elevation of the device mounted on a vehicle.

Figure 2 is a vertical section on line 2-2 of Figure 3;

Figure 3 is a vertical section on line 33 of Figure 2.

Figure 4 is a horizontal section on line 4ld of Figure 3.

Figure 5 is an end elevation with parts removed.

Figure 6 is a sectional perspective of a valve having a valve port therein.

Figure 7 1s a perspective partly sectioned of the valve cooperating with the port shown in Figure 6.

Figure 8 is a section on line 88 of Figure 2.

Figure 9 is a section on line 9-9 of Figure 2.

Figure 10 is a vertical section showing a difierent embodiment of the invention.

Figure 11 is a detail ot the valve used in the embodiment shown in Figure 10.

Figures 12, 13, 14, and are sections taken on the correspondingly marked lines of Figure 11.

Figure 16 is a view similar to Figure 10 but showin a modification.

Figure 1 is a detail in perspective oil a part used in this modification.

Figure 18 is similar to a portion 0t Figure 2, but on. a larger scale.

Referring first to the form shown in Figures 1 to 9 and 18, the device comprises a closed casing 1 having perforated lugs 2 tor the passage of securing bolt 3 by which the casing may be made fast to a vehicle body or 4Lira-me, one member of which is indicated at The lower portion of the casing 1 is formed as a cylinder 5 within which is reciprocable a piston 6 forming with the cylinder a pressure chamber beneath the piston. As shown this piston comprises a cylindrical portion 7 fitting within the cylinder and having a transverse web 8. This web is formed with a port 9 therethrough with which cooperates a valve 10. Above the web 8 are a pair of alined perforations for the reception of apin12 which may be tired from rotation therein by means ot' a transverse key pin 13 (see Figure 3). The pin 12 passes through a bushing 14 earned within a transverse perforation in the lower end of the link 15. The upper end of this link is bifurcated for the reception of a pivot pin 16 by which the link is pivoted to an arm 17 made last to a rock shaft 18. This rock shaft is journaled in bosses 19 extending inwardly from the u per portion of the easin at one side 0 the axis of the cylindrlcal portion 5. At one side of the casing the shaft 18 rejects outwardly thereof throu h a stug box 20 of any suitable type or insuringv a fluid tight joint between the shaft 18 and this casing.

@utwardly of the stug box, shalt 18 has fixed thereto an arm 22 the outer end of which is pivotally connected, reterably by a ball joint to the upper end 0 a l 23, the lower end of which is connected lb a similar ball joint to a member 2% made net to a vehicle axle 25. This axle is coected to the member 4 of the body or vehicle frame by means of a s ring 26 pivoted at its torward end 27 to t e meber t and supported Mill lltfll are at its rear end by. a pivoted link28 depending therefrom. The particular connection of the spring with the vehicle, however, forms no part of the resent invention, any form of mountin the vehicle from the axle which may e desired being utilized. I

-With this connection it is evident that on relative up and down motion between the axle and the vehicle, rock shaft 18 is rocked through the arm 17 and link 15, and the piston 6 is reciprocated in the cylinder. The lower end of the cylinder is closed as shown at 30 to form beneath the piston a chamber for the reception of a liquid such as oil or glycerine, but the use of any other fluid such as air or air and oil is within the scope of this invention.

The valve 10 above mentioned seats upwardly against the port 9 to close communication through the piston to the chamber therebeneath. Its valve is normally held in closed position by means of a coiled spring 35 reacting between the lower face of the valve and a flanged ring 36 made fast to the lower end of the piston, this construction being such that on raising the piston within the cylinder, valve 10 is forced from its .seat and fluid positioned above the piston is permitted to pass beneath the piston. On downward motion of the piston, however, the valve remains tightly seated and prevents-flow of fluid upwardly relatively thereto. To permit the fluid to flow from beneath the piston and restrict it so as to cushion the rebound of the vehicle spring, this valve is shown as provided with a central cylindrical port 40 therethrough. This port leads to the lower end of a sleeve portion 41 extending upwardly from the upper face of the valve and closed off at its upper end. Through the sides of this sleeve portion are a series of openings 42 spaced lengthwise thereof which furnish escape openings for the fluid compressed beneath the piston. Slidable, within the valve port is a valve comprising a tubular member 43 which has at an intermediate point an outwardly extending flange 44 which rides in the valve port. This tubular member opens at its upper end within the sleeve 41, the internal diameter of which is smaller than the .valve port 40, while the lower end of the tubular member communicates with the space beneath the piston.

In order to vent the space between the flange 44 and the lower edge of the sleeve 41, a series of ports 45 extend through the valve 10 outwardly of the sleeve 41 from the upper end of the valve port. This space is also in communication with the interior of the member 43 by means of an opening 46 extending through /the member 43. from a peripheral groove 47. Near the lower end of the memerber 43 a flanged disk 48 is made fast thereto and a spring 50 seated within the flange of this disk bears at its upper end against the lower face of the valve 10. This spring normally urges the member 43 downward until the flange 44 contacts and is stopped by a stop ring 51 seated in a groove 52 near the lower end of the valve port. In this position of the parts the openin s 42 are uncovered by the reduced end 0 the valve member 43 so that fluid may flow through the member 43 into sleeve 41 and out through the openings 42, thus furnishing a restricted passage for the fluid.

In case of a descent of the piston the increased pressure therebeneath moves the member 43 upwardly, the pressure reacting against the lower end of the member 43 and the lower surface of the flange 44. This motion of the member 43 causes the openings 42 to be closed progressively, thus additionally restricting the passage of fluid, the amount of such restriction depending on the increase of pressure beneath the piston which is dependent on the speed of descent of the piston. At its limit of upward movement the groove 47 is in alinement with the lower openings 42 while the upper end of member 43 is above the highest opening so that the entire relief for the pressure is through the openings 46 and 45. The greater the speed of such descent, it is evident the greater the pressure developed therebeneath due to the restricted relief for the pressure.

While the amount of restriction to the flow is dependent on the pressure beneath the piston, as above stated, there is also another factor dependent on the speed of the action and more or less independent: of the pressure. The passage through the member 43 is so restricted that pressure exerted beneeath the piston is not immediately active above this member within the sleeve 42. There is, therefore, on a sudden actuation a momentarily increased pressure acting on the lower end of member 43, uncounterbulanced by equal pressure on its upper end. This uncounterbalanced pressure increases the extent of relative movement of the piston and member 43 to further restrict the flow. If the motion is slow the pressure at both ends of the member 43 is more nearly equal and the-pressure acting to move it relative to the piston is more nearly limited in its action to the area of the lower side of the flange 42. This action decreases the effectiveness of the spring 50 in holding the fluid passage as open and free as possible when the rebound action to be cushioned is sudden.

In Figures 10 to 15 is shown a modified construction in which is provided a closed casing 100 having ears 102 by which it may be made fast to the vehicle body and which has therein a fluid pressure cylinder 105. Within this cylinder is mounted a piston 106 to the upper end of which is pivoted a link 107 connected to an arm 108 with a lit naeaeoe rock shaft 109, this rock shaft passing outwardly of the casing and being connected to the axle for rocking motion similar to the rock shaft 18 of the form first described.

The lower end of the cylinder 105 is spaced above the lower end of the casing and has formed therein a port 110. lln communication with this port is a sleeve 111 seated within the lower end of the cylinder and cooperating with the upperend of this sleeve is a valve 112. The stem 113 of this valve extends downwardly through a guide member 11 1 extending across the sleeve 111, and surrounding this stem 11 1 is a spring 115 reactin against the lower face of the guide 1141 an a cover 116 supported on the stem by means of a transverse pin 117. This valve 112 lifts to permit the flow of fluid from the casing 1 into the cylinder 105, but

prevents flow in the reverse direction. To permit a restricted flow out from the cylinder a tubular valve or member 120 is provided. The inner end of this valve 120 at 121 is slidable through an opening 118 in Y the side wall of the cylinder, a flange 122 on the portion 121 normally engaging a tubular extension 123 of the cylinder wall. This tubular member 120 has a reduced portion 124: which extends into a cap 125 threaded in the outer wall of the casing 1, and communicates at one end with the cylinder 105beneath the piston and at the other end within the cap 125, while positioned longitudinally thereof a series of openings 126 and smaller openings 127 extend from the central passageway through the side walls thereof. 1 I

Un outward sliding movement of member 120 these openings 126 and 127 are designed to pass within the sleeve 125 so as to be progressively covered thereby and additionally restrict the passage of fluid outwardly from the cylinder to the interior of the casing. The valve member 120 is normally held with the flange 122 against the tubular portion 123 by means of a spring 130 surrounding valve member 120 and reacting between the flange 122 and the inner end of the plug 125. As shown a spring 135 is positioned within the cylinder 105 and reacts between the valve seat member 111 and the lower face of the piston 106, this spring normally holding the piston in its elevated position. In this construction it is unnecessarv to use a rigid link connection between ihe body and axle of the vehicle as indicated 0y link 23 in Figure 1, a flexible member such as a strap or cable being used. if desired instead, the spring 135 keeping the strap or cable in taut condition. In this form of the device upward movement of the piston is unrestricted, thevalve 112 opening readily to permit flow of fluid into the cylinder therebeneath, The downward motion of the piston is restricted, however, since fluid must pass through the tubular member 120 and escape from the lateral openings 126 and 127. If the speed of downward movement of the piston is considerable the pressure produced beneath the piston causes the valve member 120 to move outwardly first cutting off the lateral openings 126 and on further motion cutting off serially the lateral openings 127. As shown the openings 126 are of considerably greater area than those shown at 127 so that the-rate of restriction to flow is. increased rapidly at first and then more slowly as the pressure increases.

In this form of the device also, the small size of the passage through the valve member causes a lag in the bulding up of pressure against its end within the sleeve 125, so that the pressure within the cylinder caused by sudden movements is more effective in overcoming the tension of spring 130, and moves member 120 further to a more restrictive position, than if the same pressure were applied more gradually. This principle of increasing the effective pressure area on a valve on sudden increase of pressure is re garded as valuable, and as a further illustration its embodimentin a diflerent form of the device is shown in Figures 16 and 17 in which, however, a different principle of obtaining the cushioning or shock absorbing action is employed.

As shown in Figure 16 this device is of the general construction shown in Figure '10, having a piston 1060 slidable in a cylin der 1050, and having a valve member 1200 with a central bore therethrough opening at opposite ends into the lower portion of the cylinder 1050 and into a closed cap 1250 similar to the cap 125 of Figure 10. In this device, however, the relief for the pressure is through a small port 1061 in the piston 1060, a ball valve 1062 being employed to prevent reverse flow into the space beneath the piston 1060. The valve 1200 in this construction permits the relief of pressure heneath the piston when it reaches a desired maximum. For this purpose the central perforation of the member 1200 has one or more lateral openings 1260 extending outwardly therefrom. which, when the valve 1200 is seated against the seat portion 1230 of the pressur cylinder, are closed ofi by the walls of this seat. The valve 1200-is normally held in seated position by means of a spring 1300 reacting between the inner end of the plug 1250, and the flange 1220 of the valve. On suflicient pressure being exerted within the cylinder the tension of the spring 1300 is overcome and the member 1200 is pushed into the cap 1250, thus opening the passages 1260, and permitting the escape of fluid from within the cylinder. The passage through the member 1200 is so restricted that on sudden increase of pres: sure within the cylinder there is a lag 111 dition of vthe fluid, such as oil, due to change in temperature. For example, when. the weather is cold and the fluid is sluggish &

the time required to build up the pressure within the cap 1250 is considerably longer than in warm weather when the fiuidfiows freely, so that a less sudden and extensive pressure within the cylinder is suflicient to.

open the relief valve. Under such conditions also the relief of the pressure through the port 1061 is less so that an earlier actuation of the relief valve is desirable. In this form of the device there is no graduated modification of the extent of restriction to the flow depending on the pressure within the pressure cylinder or the speed of the "pressure movement of the piston except when the pressure is excessive. It does, however, make use of the delayed transmission of pressurev through a restricted passage in order to modify the normal action of the device at certain times.

It is evident, of course, that the openings l2 shown in the first form of the mechanisminay progressively decrease in size or be more restricted in number lengthwise of the sleeve in order to 1m art a variable increase of resistance to t e flow of fluid with the decrease or increase of pressure beneath the piston and consequently of speed of recoil.

interposing a resistance to the relative move ment of said members in the opposite direction depending in extent directly on the speed of relative movement of said members.

2. A shock absorber comprising a cylinder, a piston movable in said cylinder, means permitting the flow of fluid to said cylinder beneath said piston but preventing flow in the reverse direction, and means responsive to increasing and decreasing pressure beneath 1,ese,eoe

said piston for interposing increasing and decreasing resistances, respectively, to the passage of fluid pressure from beneath said piston. v

3. In a shock absorber, a pair of members comprising a cylinder and a piston in said cylinder, said members being constructed to be interposed between a vehicle body and axle, a air of ports communicatin with said cylinder, a valve in one of. sai ports permitting flow. through said port freely in one direction and closing against flow in the opposite direction, and a valve in said other port permitting restricted flow when said first port is closed, the extent of restriction being variable and increasing with increased pressure of fluid thereagainst.

4-. Ina shock absorber, a cylinder, a piston movable in said cylinder, means for connectmg said piston and cylinder intermediate a ve icle body and axle, a pair of ports communicating with said cylinder beneath said piston, a valve in one of said ports permitting free flow to said cylinder beneath said piston but closing to prevent escape of fluid therefrom, a tubular valve slidable through the other of said ports, a guide sleeve having its outer end closed for guiding said tubular valve and into which the tubular portion opens, said guide sleeve having a series of openings through its side wall spaced length- Wise thereof, and a spring normally holding said tubular valve inwardly toward said cylinder, whereby said tubular valve normally uncovers the maximum number of said openings, but is movable under increased pressure beneath said piston to progressively clom said openings to interpose increased resistance to the passage of fluid.

5. In a shock absorber, a cylinder, a piston movable in said cylinder, means for connecting said piston and cylinder intermediate :1 vehicle body and axle, a port communicating with said cylinder beneath said piston, a tubular valve slidable in said port and having a portion of reduced diameter, a sleeve having its outer end closed for closely guiding the outer end of said sleeve portion and into. which fluid may flow through said valve, said sleeve having a series of openings spaced longitudinally thereof for the escape of fluid therefrom and adapted to be closed serially by movement of said reduced portion into said sleeve, a spring urging said reduced portion outwardly from said sleeve. and means permitting ready flow into said cylinder beneath said piston.

6. Ina shock absorber comprising a cylinder, a piston movable in said cylinder, and means for connecting said piston and cylinder intermediate a vehicle body and axle, the combination of a pair of ports communicating with said cylinder beneath said piston, a valve in one of said ports permitting free flow to said cylinder beneath said meaeoe piston but closing to prevent escape of fluid therefrom, a tubular valve slidable through the other of said ports, a guide sleeve having its outer end closed for g'uidin said tubular valve and into which the tu ular portion opens, said guide sleeve having a series of openings throughout its side wall spaced lengthwise thereof, said openings being. of preferably greater area toward one end of said sleeve than at the other, anda' sprin normally holdingsaid tubular valve towar said cylinder, whereby said tubular valve normally uncovers the maximum number of port therethrough and a sleeve portion closed at its outer end and having openings spaced longitudinally thereof and in communication with said valve port, a tubular valve slidable in said valve port and sleeve and opening at opposite ends into said 0 linder beneath said piston and into said slieeve and slidable in said sleeve to cover or uncover more or less of said sleeve openings, and a spring normally holding said tubular valve in a osition to uncover said openings.

8. In a ock absorber comprising a cylinder, a piston movable in said cylinder, and means for connecting said piston and cylinder intermediate a vehicle body and axle, the combination of a ort through said piston, a valve coo eratlng withsaid port to prevent flow of. uid from said cylinder beneath said piston but permittin flow in the reverse direction, a port throug said valve, a tubular member carried by said valve slidabl in said valve port, a sleeve closed at one en and fixed at its other end to said valve and having openings throu h its side spaced longitudinally thereof, sai tubular member extending within said sleeve and closing ofl more or less of saidopenings by sliding in said valve port, a spring reacting between said piston and valve to urge said valve closed, and a spring reacting between said valve and member to normally maintain said'opening uncovered.

9. In a shockabsorber, a cylinder, a piston movable in'said cylinder, a pair of ports communicating with 'the space beneath said piston, a valve in one of'said ports opening to permit flow inward beneath said piston and closing to revent outflow, a valve member for contro ling the other. of said ports and having a perforation therethrough opening at one end intothe space beneath said piston, a sleeve member closed ofl at one end and sildably receiving said valve member, the opposite end of said perforation opening into said sleeve, and a spring urging said valve member from said sleeve member, one of said members having lateral escape perforations serially closed by movement of said valve member against the force of said spring to effect a variable restricted passage for the escape of pressure from beneath said piston through the perforation of said valve member.

10. In a shock absorber, a cylinder, a

piston in said cylinder, an outlet for pressure in said cylinder beneath said piston a valve for controlling said outlet, said va ve having a constricted passage therethrough in communication with the s ace beneath said piston, a chamber into which said valve extends and with the interior of which said passage conimuncates, and a spring urgin said valve into seating engagement with sai outlet.

11. In a shock absorber, a pressure chamber for the reception of a fluid, an outlet for said chamber, a valve subjected to pressure from said chamber for controlling said out-' let, a spring urging said valve in opposition to said pressure, and means acting to in-.

crease the effective area of said valve subjected to pressure on sudden increases of pressure in said chamber.

In testimony whereof we have affixed our signatures.

ELLIOTT S. CHURCH. FREDERICK J. SHEPARD, JR. 

